snowball (n.) Look up snowball at Dictionary.com
c.1400, from snow (n.) + ball (n.). Snowball's chance (in hell) is recorded by 1910.
snowball (v.) Look up snowball at Dictionary.com
"to make snowballs," 1680s, from snowball (n.); sense of "to throw snowballs at" (someone) is from 1850. Meaning "to increase rapidly" is attested from 1929, though the image of a snowball increasing in size as it rolls along had been used since at least 1613, and a noun sense of "a pyramid scheme" is attested from 1892. Related: Snowballed; snowballing.